Fair Test:
To make sure this is a fair test I will keep the sand the same level throughout to assure my results are correct. I will not change the type of sand, as the sand grains and consistencies vary in size. The clamp stand and depth of crater produced should be measured accurately to obtain correct results. The same marble should be used for each reading three times so I can take an average, this way it will not affect the experiment if I get an odd result.
Safety:
I will wear safety goggles during this experiment to prevent sand getting in my eyes. I will need to be careful while adjusting the clamp stand as I could hurt my fingers.
Prediction:
I predict that the higher the marble is dropped from the stand, the deeper the crater will be. Once the marble is released kinetic energy will take effect on the marble. I think this is because the marble is at the top of the stand and the gravitational energy on the marble is very high. Once the marble is halfway down both of these forces are equal so the higher the marble is dropped then the more kinetic energy it will have making the crater become deeper. Terminal velocity is the steady speed reached by the marble when its weight is balanced by friction. This is very important because the marble could be dropped from two different heights and still travel at the same speed, causing the same depth of crater in the sand. Air resistance is also a problem; this is the force of friction on the marble when it moves through the air. This could slow down the marble.
Results:
Analysis:
My results show that the higher the marble was dropped from, the deeper the crater. The average of my results show this pattern. I can see that as the height was increased, so did the depth of the crater. I think this happened because at the top of the stand the gravitational energy was higher. My prediction was correct as terminal velocity did have an effect on the marble as the average was 25mm for 90cm and 100cm. This shows the marble was travelling at the same speed for the different heights.
Evaluation:
The method I used was suitable, although I would like to have used something else instead of a clamp stand fro dropping the marble as I found it difficult to make sure I released it correctly. I could use different heights to get a good range of results. I found that measuring accurately was important so there wouldn’t be any odd results. I ensured my results would be accurate by measuring, carefully, the height of the clamp stand and level of sand. I didn’t change the sand or the marble; the same equipment was used throughout. This investigation could be improved by doing more than one attempt to find a larger range of results. To extend the experiment, you could try it with marbles of different size and shape. I found this experiment quick and easy to complete.
Selina Kantepudi
